You can also visit Assateague Island National Seashore on both the Maryland and Virginia sides for free. Speaking of "free," this is where wild ponies run free, and you can camp right on the beach, bonfires and all.

The fee waiver includes entrance fees, commercial tour fees and transportation entrance fees. If you want to go camping or participate in other activities that charge, you'll still have to pay for those.

The Park Service also reminds you even more national parks never charge admission -- check out these here.